Triggering Reversible Optical Transformation of Monolayer WSe₂ via Photoswitchable and Cleavable Solid Azobenzene...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDCs) exhibit unique properties for advanced electronics.
• Azobenzene molecules offer a tunable platform for manipulating material characteristics.

Purpose of the Study:

• To engineer the physical properties of monolayer tungsten diselenide (WSe2) using azobenzene derivatives.
• To investigate the interface interactions and doping effects in WSe2/azobenzene heterostructures.

Main Methods:

• Fabrication of van der Waals heterostructures using photoswitchable azobenzene polycrystals.
• Utilizing visible laser-driven isomerization to induce trans-to-cis conversion in azobenzene.
• Characterization via temperature- and gate-dependent photoluminescence (PL) and surface potential measurements.

Main Results:

• Observed significant electron doping variations in monolayer WSe2 due to azobenzene isomerization and phase transition.
• Demonstrated distinct PL quenching and a shift from neutral excitons to negative trions.
• Confirmed changes in surface potential of WSe2 and the heterostructure.

Conclusions:

• Developed a method for selective and reversible engineering of 2D materials.
• The approach facilitates the creation of novel information processing and photoresponsive devices.
• Potential applications include molecular probes and advanced optoelectronic systems.